There is no such percentage. The entire amount which will qualify for a day's work will be considered as Basic Salary. Alternatively, the amount which is considered for deduction if you take a day leave without pay is your basic pay. Obviously, if you are given an accommodation free of rent, the rental value of that accommodation is outside the scope of remuneration. Similarly, if you are reimbursed the rent paid by you or petrol expenses or telephone expense incurred by you, that can also be excluded from your salary.